window.onload=function(){
				var item = document.getElementsByClassName("item");
				var it = item[0].getElementsByTagName("div");
				
				var content=document.getElementsByClassName("content");
				var con = content[0].getElementsByTagName("div");
				for(let i=0;i<it.length;i++){
					it[i].onclick=function(){
						for(let j=0;j<it.length;j++){
							it[j].className='';
							con[j].style.display="none";
						}
						this.className="active";
						it[i].index=i;
						con[i].style.display="block";
					}
				}
			}